// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_VIDEO_TRACK_ADAPTER_H_
#define CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_VIDEO_TRACK_ADAPTER_H_

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/thread_checker.h"
#include "content/public/renderer/media_stream_video_sink.h"
#include "content/renderer/media/webrtc/webrtc_video_capturer_adapter.h"
#include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
#include "third_party/webrtc/api/mediastreaminterface.h"

namespace content {

class MediaStreamVideoTrack;
class PeerConnectionDependencyFactory;

// MediaStreamVideoWebRtcSink is an adapter between a
// content::MediaStreamVideoTrack object and a webrtc VideoTrack that is
// currently sent on a PeerConnection.
// The responsibility of the class is to create and own a representation of a
// webrtc VideoTrack that can be added and removed from a RTCPeerConnection. An
// instance of MediaStreamVideoWebRtcSink is created when a VideoTrack is added
// to an RTCPeerConnection object.
// Instances of this class is owned by the WebRtcMediaStreamAdapter object that
// created it.
class CONTENT_EXPORT MediaStreamVideoWebRtcSink : public MediaStreamVideoSink {
public:
    MediaStreamVideoWebRtcSink(const blink::WebMediaStreamTrack& track,
        PeerConnectionDependencyFactory* factory);
    ~MediaStreamVideoWebRtcSink() override;

    webrtc::VideoTrackInterface* webrtc_video_track()
    {
        return video_track_.get();
    }

    rtc::Optional<bool> SourceNeedsDenoisingForTesting() const;

protected:
    // Implementation of MediaStreamSink.
    void OnEnabledChanged(bool enabled) override;
    void OnContentHintChanged(
        blink::WebMediaStreamTrack::ContentHintType content_hint) override;

private:
    // Helper to request a refresh frame from the source. Called via the callback
    // passed to WebRtcVideoSourceAdapter.
    void RequestRefreshFrame();

    // Used to DCHECK that we are called on the correct thread.
    base::ThreadChecker thread_checker_;

    // |video_source_| and |video_track_source_proxy_| are held as references to
    // outlive |video_track_| since the interfaces between them don't use
    // reference counting.
    class WebRtcVideoSource;
    scoped_refptr<WebRtcVideoSource> video_source_;
    scoped_refptr<webrtc::VideoTrackSourceInterface> video_source_proxy_;
    scoped_refptr<webrtc::VideoTrackInterface> video_track_;

    class WebRtcVideoSourceAdapter;
    scoped_refptr<WebRtcVideoSourceAdapter> source_adapter_;

    // Provides WebRtcVideoSourceAdapter a weak reference to
    // MediaStreamVideoWebRtcSink in order to allow it to request refresh frames.
    // See comments in media_stream_video_webrtc_sink.cc.
    base::WeakPtrFactory<MediaStreamVideoWebRtcSink> weak_factory_;

    DISALLOW_COPY_AND_ASSIGN(MediaStreamVideoWebRtcSink);
};

} // namespace content

#endif // CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_VIDEO_TRACK_ADAPTER_H_
